Reading back through this thread I don't think my issue has to do with just upgrading to the new firmware 5.18.2 yesterday. I'm in no way an expert but thought my observations today were interesting.
I'm on my third PW and am running a Kindle Paperwhite 5 - Gen 11 2022. I normally have Wi-Fi off to save on battery power. I've used PWs since 2012 and Calibre as long as I can remember. I process almost exclusively library borrowed eBooks through Calibre and side load them. None are stored on Amazon's cloud. I've been through the book cover issues and resolved them.
Today I turned on Wi-Fi for the first time in a few weeks. All of my eBooks disappeared, but all of my personal documents were fine. Looking at my device content on Amazon there was none. Even though I side-load the eBooks I had kept Amazon's "Collection" organization synced when I add a new eBook. Long story but it was beneficial when switching to a new PW. They had wiped out everything on the Amazon website.
I had just imaged my PW yesterday luckily. I'm talking about a full drive image. So I restored the complete image to my PW. I left PW's Wi-Fi connected. Started it up but while my "Collection" labels were in place all of the eBooks were stored under Uncollected. I have quite a collection organization, so this was going to be a chore.
Again, leaving the Wi-Fi on I restarted the PW. All of my "Collections" got re-populated except for 20 eBooks for some reason.
I assigned them to "Collections", held my breath and restarted again. Everything stayed and no eBooks were removed. I turned off Wi-Fi and imaged the PW again. Don't have the nerve to turn Wi-Fi back on today...
